Two ways to do this:
1. Keep the history. Convert every commit, create tags from tags and branches from branches. Branches/tags from releases would probably be a good thing to keep too but this has to be tested.
2. Abandon history. The history is still at Tigris for those that want to dig into that.

Work to be done and suggested order:
1. Announce the work. (done)
1. Transfer the contents of the argouml.tigris.org project (the main project). (done)
1. Move all the code into the repository at github. (done)
1. Resolve the testmodels problem by keeping a copy. (done)
1. Remove the code from the tigris repository. (done)
1. Transfer the contents of the argouml-actionscript3, argouml-cpp, argouml-csharp and argouml-java projects. (done)
1. Announce that development can continue in the main repositories. (done)

After this the work has several independent tracks:

|| Get the argouml/tools/maven/toppom.xml builds to work (done) -moving it to separate repository-. || Transfer the contents of each of the rest of the projects || Maven-based releases. ||
|||| Set up repo. Describe how to work with repo. (done) || ||
|| Set up gerrithub. (done) || Get them to build individually adding each to the repo configuration. || ||
|| Modify the repo configuration to point to gerrithub. (done) || || ||
|| Describe how to do development using gerrithub. (done) || || ||
|| Set up build server. || || ||
|| Check that developing using Eclipse works (egit against gerrithub). || || ||